I just try to maintain the perspective that, such questions/comments tell me more about that person and their life experiences, than about me and mine. I find it enjoyable to turn the conversation to the asker's own kids/family. A lot of this is motivated by people's own powerful emotional memories, and by letting them talk about that instead, it turns the attention away from me.
It doesn't make them any less rude, but it helps me not walk around feeling defensive. If I can find a way to pull a warm fuzzy out of a situation, I will.